The present invention relates to a beverage, a beverage container including a beverage, a method of producing a beverage and a beverage production plant.
Producers of carbonated beverage, in particular breweries, constantly seek to improve the flavour of their beverage. It is well known that humans perceive the flavour of e.g. beverage via taste buds located on the tongue. Thus, in order to alter the flavour of the beverage, the chemical composition of the beverage may be changed in order to influence the taste buds differently. Other ways of changing the taste of the beverage not involving changing the chemical composition of the beverage include modifying the temperature at which the beverage is served. Carbonated beverages are generally served cool, at about 10° C. At lower temperatures, the taste buds are generally less sensitive to flavours whereas at higher temperatures, carbonated beverages do generally appear less “fresh”. The “freshness” of the beverage may also be increased by increasing the carbonization of the beverage and thus making the beverage slightly prickling on the tongue of the drinker, however, beyond a certain carbonization level the taste of the beverage will be negatively influenced by the large amount of bubbles in the beverage causing a strong prickling effect on the tongue of the drinker and by the sour taste of the carbon acid generated. It is of course contemplated that there are no strict rules when discussing the taste of a beverage, since the taste experience may vary significantly between individual beverage drinkers.
In experiments it has been observed that when certain beverages are submitted to isothermal compression then, contrary to the general expectation of the incompressibility of watery phases, a compressibility of about 0.1% per bar can be measured. It has also been observed that when certain beverages are submitted to an abrupt deceleration, such as can happen when the beverage container is accidentally dropped to the floor, a sudden pressure jump of about 2 bar can be measured inside the container, after which a slow reversal to the initial lower pressure conditions can be observed at a rate approximating 1 mbar/min. In both of the above situations it was observed that the beverages at all times remained clear and void of opaque components during the above experiments.
It is contemplated that the above experimental findings can be rationalized according to the following model, wherein the presence of CO2-filled ultra fine bubbles within the observed beverages which have sizes below the Abbe-diffraction limit of about 80 nm and are present in equilibrium with dissolved and partially dissociated CO2 is proposed. Such ultra fine bubbles would be compressible, non-visible and have access to the surplus of CO2-gas necessary to undergo the observed abrupt pressure increase when abruptly decelerated. Usually, as such ultra fine bubbles are not expected to be stable as their sizes are below the LaPlace-limit given by P=2*γ/r, wherein P is the pressure inside the bubbles, γ the surface tension of the beverage and r the radius of the bubble, it is further contemplated that amphiphilic components in the beverages such as fatty acids and the like could contribute to lowering the surface tension to such levels that the presence of the proposed ultra fine CO2-bubbles in the examined beverages can exist through either thermodynamical or kinetical stabilization. Potentially, such an amphiphilic layer could contribute to an additional dissolution of CO2 within the amphiphilic layer, further serving as a reservoir for CO2 within the beverage.
Calculations based on the above reported experimental results have shown that the number of bubbles in one liter of beverage prepared according to the invention can be as high as 1015 to 1021 bubbles per liter of beverage, which corresponds to molar concentrations ranging from about 0.1 ppb and up to about 100 ppm. It is contemplated without otherwise considering the below presented model restrictive for the contents of the invention, that the stability of the bubbles created inside the beverages examined can be rationalized by one or several thermodynamical models of bubble-nucleation. E.g. in one such model, commonly classified as a self-consistent theory of nucleation (see e.g. S. L. Girshick, C.-P. Chiu, J. Chem. Phys., 93(2), pp 1273-1277, 1990), it is proposed that stable nucleation cores, such as i.e. micro-bubbles, may exist within homogeneous and heterogeneous phases, such as the watery phase of the beverages examined, when the surface tension of the nucleation cores is balanced by the degree of supersaturation up to a limiting concentration of nucleation cores whereupon macroscopic nuclei are observed such as e.g. visible carbon dioxide bubbles in carbonated beverages.
In beverages prepared according to the present invention, supersaturation of the carbon dioxide pressure is achieved by applying additional pressure to the beverages, thereby substantially reducing or even eliminating any development of headspace above the beverages prepared according to the present invention. The relatively high pressures used to achieve this effect surprisingly cause less bubbles to form when the beverages prepared according to the present invention are poured, which permits a stronger carbonization desirable in e.g. beers of various varieties while maintaining or surprisingly even enhancing the effervescent effect of carbon dioxide upon drinking through an observed faster release of macroscopic bubbles.
Surprisingly and most importantly, it has now been realized by the inventors that the isostatic compression of some kinds of beer and other CO2-containing beverages (such as e.g. soft drinks) fulfilling certain specific requirements that were already at equilibrium pressure with a gaseous CO2-phase external to the aqueous phase (a headspace), upon compression to the above described super-equilibrium pressure (whereby the headspace is substantially reduced or even eliminated) has a profound influence on the taste, which becomes sweeter, milder and less prickling on the tongue. Further beverages prepared according to the present invention have been found to be acceptable to drink at higher temperatures compared to their regular counterparts, consequently allowing the beverages prepared according to the present invention to be served at increased temperatures as compared to their regular counterparts. This represents another advantage of the beverages prepared according to the present invention as the cooling of beverages to palatable pleasant temperatures constitutes a major economic and environmental limitation within the beverages industry.
The generation of the bubbles in carbonated beverages and other liquids has been the subject of intense research. Some prior art documents relating to carbonated beverages and similar liquids, as well as containers for holding such beverages and liquids, are presented below:
In the scientific paper titled “Superstability of Surface Nanobubbles” of the “Physical review letters” of the American Physical Society dated 18 May 2007, it has been revealed that nanobubbles are stable for hours even when reducing the water pressure.
The scientific paper titled “Surface Tension Module” by John W. M. Bush of the Department of Mathematics, MIT, teaches that the pressure within the bubble is higher than that outside by an amount proportional to the surface tension, and inversely proportional to the bubble size.
In the scientific paper titled “Bubble population phenomena in acoustic cavitation” by T. G. Leighton, Ultrasonics Sonochemistry 1995 Vol 2 No 2, it is suggested that the size of the bubble and the nature of the local sound field determine whether the bubble oscillations are spherical or non-spherical.
In the scientific paper “CO2—Hydrophobin structures acting as nanobombs in beer”, published in Monatsschrift für Brauwissenschaft vol: 63 issue: ¾ pages: 54-61, it is suggested that the hydrophobins' association to CO2 nanobubbles is acting as “nanobombs” and perhaps as “nucleation sites” causing overfoaming of the carbonated beverage.
In the book titled “The Acoustic Bubble” of T. G. Leighton, Institute of Sound and Vibration Research, The University of Southampton, UK, published by Academic Press Limited, it is suggested that organic impurities such as fatty acids may accumulate on the wall of a bubble. In this manner, a bubble nucleus would be stabilized against dissolution.
WO 2009/071085 of the applicant company discloses an adapter set for use in combination with a collapsible beverage container and a beverage dispensing system. The beverage dispensing system includes an inner chamber, a pressurizing device and a cooling device.
EP 2014432 and EP 2242636 disclose a multi container comprising an inner stretch blow moulded part being loosely positioned within an outer stretch blow moulded part. Further documents disclosing various multi containers or bag-in-kegs include U.S. Pat. No. 6,209,344, US 2010/0243596, WO 2011/002293, WO 2008/129012, WO 2008/129015, WO 2008/129018 and WO 2008/087206.
EP 2080709 discloses an assembly of a container and a closure. The closure comprises two access ports.
WO 2010/119056 of the applicant company discloses a self regulating and constant pressure maintaining product dispenser. The dispenser is inherently capable of substantially maintaining the initial pressure in the pressure space by releasing or adsorbing propellant gas.
WO 2008/000271 discloses the use of insoluble gas in beverage to provide a more pleasant and smooth mouth feeling experience perceived by the drinker.
U.S. Pat. No. 6,209,855 discloses a method for mixing discrete microscopic portions of gas in a liquid.